463 research outputs found

    Effects of Task-Modality Fit on User Performance

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    Exploring the Factors Enhancing Member Participation in Virtual Communities

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    The purpose of this study is to find the factors that enhance member participation in virtual communities. Although there are many factors influencing member participation, this study limits its independent variables to those of managing strategy and information system quality. In addition to finding their direct impacts, this study identifies indirect effects through two mediating variables such as member visit and sense of community. The result of this study revealed that there was no significant direct path from managing strategy to participation. However, the path from sense of community to participation was strongly supported by the results. This then implies that a manager of a community has to emphasize the sense of community, membership in particular, in order to enhance participation. In addition, the results showed that sense of community could be enhanced by an appropriate managing strategy, while the number of visits could be increased by the information systems quality.</p

    Online Comment Moderation Policies for Deliberative Discussionā€“Seed Comments and Identifiability

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    Due to the development of media information technologies and the proliferation of mobile devices, the Internet has rapidly moved to the center of news readership. In contrast to traditional media, Internet news is often coupled with commenting platforms that can accommodate readersā€™ immediate feedback to news stories. However, a side-effect of this featureā€”malicious commentsā€”is becoming an increasingly serious social problem. To alleviate this problem and increase the likelihood of comments functioning as deliberative discussion, we suggest two moderation policiesā€”a policy of providing high-quality seed comments and a policy of increased identifiability through social networking service accountsā€”and examine their effects through a longitudinal online experiment. We designed experimental groups according to a 2 x 2 between-subjects factorial design. For our experiment, a total of 137 subjects read news stories and commented on them over 15 days by using a mobile Android application developed specifically for the experiment. We found the following relationships. First, both seed quality and identifiability improve the quality of user comments in terms of deliberative discussion. Second, these effects are comparable in magnitude. Third, there are no significant interaction effects between seeds and identifiability. Fourth, the effects of high-quality seeds disappear early with anonymous users but persist when users are identified by social media accounts. Fifth, the negative effects of low-quality seeds are present and persistent only when combined with anonymity. Otherwise, the negative effects of low-quality seed comments are canceled out by the positive effects of identifiability. Finally, anonymous males are easily provoked to respond to low-quality seed comments, but most females do not respond to such comments even in anonymous situations

    Maca (L. meyenii) for erectile dysfunction: a systematic review and meta-analysis

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    Maca (Lepidium meyenii) has been reported to improve erectile function (EF). The purpose of this study was to evaluate the clinical evidence for or against maca as a therapy for erectile dysfunction (ED) in men. We searched 11 databases for randomized controlled trials (RCTs) comparing any type of maca with a placebo in the treatment of ED in men. The primary endpoint was EF, while the secondary endpoints were quality of life and adverse events. Risk of bias (ROB) was assessed using the Cochrane ROB tool 2.0. Study selection, data extraction, and assessment were independently performed by two researchers. RevMan 5.4.1 software (Cochrane Collaboration, 2020) was used for data aggregation, and the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) assessment was used to evaluate the quality of the study outcomes. Only two RCTs met all the inclusion criteria. These RCTs examined the effects of maca on EF in patients with mild ED. One RCT showed a positive effect of maca on EF, whereas the other RCT did not. The results of the meta-analysis indicate that maca has positive effects on EF in men with mild ED (n = 79, MDs 1.13: 0.64 to 1.61, p = 0.01; p < 0.0001). Our comprehensive review found limited evidence for the benefits of maca in improving EF. Several limitations, including the total number of studies and their sample sizes, were insufficient to draw firm conclusions. Further studies are needed

    Superconformal Cu Electrodeposition on Various Substrates

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    For application to Cu interconnection, superconformal electrodeposition has been performed on various substrates, including physical vapor deposited ~PVD! Cu, two kinds of electroless deposited ~ELD! Cu, TiN barrier, and metallorganic chemical vapor deposited Ru. ELD Cu with HCHO as the reducing agent was compatible with PVD Cu in terms of conformal characteristics and film continuity. Both PVD and ELD Cu seed layers enabled superconformal filling with distinct bumps. Superfilling was also attained on resistive substrates of TiN and Ru through Pd activation and subsequent slight seeding by electrodeposition to enhance the action of additives

    Identification of Domains Directing Specificity of Coupling to G-proteins for the Melanocortin MC3 and MC4 Receptors

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    The melanocortin receptors, MC3R and MC4R, are G protein-coupled receptors that are involved in regulating energy homeostasis. Using a luciferase reporter gene under the transcriptional control of a cAMP-responsive element (CRE), the coupling efficiency of the MC4R and MC3R to G-proteins was previously shown to be different. MC4R exhibited only 30-50% of the maximum activity induced by MC3R. To assess the role of the different MC3R and MC4R domains in G-protein coupling, several chimeric MC3R/MC4R receptors were constructed. The relative luciferase activities, which were assessed after transfecting the chimeric receptors into HEK 293T cells, showed that the i3 (3rd intracellular) loop domain has an essential role in the differential signaling of MC3R and MC4R. To reveal which amino acid residue was involved in the MC4R-specific signaling in the i3 loop, a series of mutant MC4Rs was constructed. Reporter gene analysis showed that single mutations of Arg220 to Ala and Thr232 to either Val or Ala increased the relative luciferase activities, which suggests that these specific amino acids, Arg220 and Thr232, in the i3 loop of MC4R play crucial roles in G-protein coupling and the subtype-specific signaling pathways. An examination of the inositol phosphate (IP) levels in the cells transfected with either MC3R or MC4R after being exposed to the melanocortin peptides revealed significant stimulation of IP production by MC3R but no detectable increase in IP production was observed by MC4R. Furthermore, none of the MC4R mutants displayed melanocortin peptide-stimulated IP production. Overall, this study demonstrated that MC3R and MC4R have distinct signaling in either the cAMP- or the inositol phospholipid-mediated pathway with different conformational requirements

    A sulfated polysaccharide of Ecklonia cava inhibits the growth of colon cancer cells by inducing apoptosis

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    We investigated anticancer effects of the crude polysaccharides (CPs) isolated from Ecklonia cava enzymatic extracts using AMG, Viscozyme, Protamex, and Alcalase enzyme against a colon cancer cell line, CT26 cells. Among them, the CP of Protamex extract (PCP) contained the highest fucose and sulfated group contents and showed the highest growth inhibitory effect against CT-26 cells. In addition, PCP dose-dependently increased the formation of apoptotic body and the percentage of Sub-G1 DNA contents. Also, PCP activated caspase 9 and PARP as regulating the expressions of Bax and Bcl-2. Moreover, PPP2, a fraction purified from PCP showed the highest growth inhibitory effect against CT 26 cells with the increased fucose and sulfated group contents. The results demonstrate that the isolated SP containing plentiful fucose and sulfated group contents has the anticancer effect on colon cancer cells via regulation of Bcl-2/Bax signal pathway

    Acceleration Effect of CuCN in Ag Electroplating for Ultralarge-Scale Interconnects

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    The addition of CuCN accelerated the deposition rate in cyanide-based Ag electroplating. The catalytic effect came from the high-order complexation of Cu with the free CNāˆ’ ions in electrolyte. It changed the equilibrium state of the electrolyte, presented as an increase in the amount of Ag CN 2 āˆ’ compared to Ag CN 3 2āˆ’. Because Ag CN 2 āˆ’ could be reduced more easily, Ag electroplating was accelerated. Fourier transform infrared analysis showed the equilibrium change with the increase in Ag CN 2 āˆ’ peak according to the CuCN addition. For superfilling, it is necessary to localize the complexation on the Cu surface.This work was supported by the Korea Science and Engineering Foundation through the Research Center for Energy Conversion and Storage RCECS , Dongbu HiTeK, and also by the Institute of Chemical Processes ICP

    Fluid-filled Giant Bulla Treated with Percutaneous Drainage and Talc Sclerotherapy: A Modified Brompton Technique

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    A 75-year-old man who was diagnosed as having a fluid-filled giant bulla was treated with a modified Brompton technique due to his poor performance status. Percutaneous drainage, suction, and talc sclerotherapy through a Foley catheter can be good treatment options for patients with conditions that are too poor to allow surgical intervention, especially if there is adhesion between a giant bulla and parietal pleura. Talc can also be used safely when mixed with normal saline as a sclerosant
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